1. Field of the Invention
The present invention relates generally to devices for personal cooling under heat stress conditions, and more specifically to personal cooling garments containing ice for use in hot environments, such as in mine rescue work.
2. Prior Art
Several types of cooling garments have been developed to alleviate heat stress problems encountered by workers in hot environments. One type of garment uses cold water that is mechanically pumped and channeled through thin tubes running throughout the garment. A second type of garment uses dry ice inserted into pockets in the garment and a third type developed in South Africa for gold mine workers uses ice. Details regarding cooling garments of each of these types may be found in the references section of Bureau of Mines Report of Investigations No. 8139 "An Ice Cooling Garment for Mine Rescue Teams" by Maria DeRosa and Richard Stein, 1976. In cold water cooling garments, the water is channeled through inner tubing and a small rupture is sufficient to render the entire garment in-effective. Such garments require a mechanical pump and a bucket of ice which are subject to failure and make the garment bulky and uncomfortable to carry. These additional parts also contribute to a high cost for such garments. Dry ice cooling garments utilize solid CO.sup.2 which sublimates rapidly and needs to be replaced every few hours. This results in extra expense, inconvenience and consumption of time. Also, because of the extreme low temperature of dry ice, insulation is required between the dry ice pockets and the wearer so as to prevent dangerous contact between the dry ice and the wearer. This insulation reduces the cooling effectiveness of the garment. Repairs of such garments in case of a bad rupture are generally costly. Current ice cooling garments utilize an excessive amount of ice, the physical dimensions of which make the garment bulky. The duration of the ice in its frozen state in such garments is generally only about two hours and since the ice bags are sewed to the jacket, the whole garment needs to be frozen which requires large freezers, large amounts of energy and longer freezing times. Having the pockets sewed to the jacket also results in the ice being exposed only on one side which reduces air circulation to the ice and reduces the cooling ability of the jacket. Having the bags sewed to the jacket also makes repairs more difficult and costly. Insulation in such garments is provided by a second garment which requires the wearing of two garments. This makes the overall garment uncomfortable to wear for long periods of time.